1. The Field of the Invention
The present invention relates to electrical computers and data processing systems. Specifically, the present invention relates to a system and method for automatically compiling address filter information.
2. The Prior State of the Art
The Internet is a worldwide interconnection of networks over which computers can exchange information. Never before have human beings had access to so much information from the comfort of their own homes or offices. For Wide Area Networks (WANs) such as the Internet, a computer typically employs a modem to send information to and receive information from other connected computers. There are many types of modems each corresponding to a specific type of medium used to deliver this information.
One common modem uses Plain Old Telephone Service (POTS) to send and receive information. POTS modems have an advantage in that they use a transmission medium that is available by just connecting the modem with the nearest phone jack. Thus, the POTS modem does not require expensive capital investment to set up a connection to the Internet. Although POTS modems are easy and inexpensive to connect to the Internet, the transmission speeds available over plain old telephone service are relatively slow. Currently, POTS modems are capable of information exchange at up to only 56,000 bits per second (bps) or approximately 0.056 megabits per second (Mbps). While faster POTS modems may eventually become available, it is not currently anticipated that POTS modems can become significantly faster due to physical limitations in the telephone lines themselves.
Telephone companies are now offering services that bypass the relatively slow telephone lines to establish a more direct connection to the Internet. For example, T1 connections permit information exchange in the megabits per second (Mbps) range. T2 and T3 connections allow for even higher speed information exchange. Currently, T1, T2 and T3 connections respectively permit information exchange at approximately 1.544 Mbps, 6.312 Mbps and 44.736 Mbps. Although these direct T1, T2 and T3 connections permit information exchange orders of magnitude faster than is available over plain old telephone service, they are typically much more expensive to obtain and/or maintain than plain old telephone service since each connection requires dedicated circuitry. Furthermore, telephone companies typically provide both the plain old telephone service and the T1, T2 and T3 connections. To facilitate free market competition, it would be desirable for a consumer to have alternative suppliers of Internet access.
A cable modem is a device that hooks up to the Internet through a cable system provided by a cable operator. Assuming that the cable operator facilitates Internet access as many cable operators do, Internet access is obtained by plugging the cable modem into a cable connection that typically already exist (or may be readily installed) in many homes and business. Thus, the cost of connecting a cable modem to the Internet is relatively small compared to establishing T1, T2 and T3 connections since the extensive cable network that supports communication already exists. Thus, there is no need to establish extensive dedicated circuitry to support each new end user.
Furthermore, dialing into the Internet is not needed since data may be communicated to or from the end-user over the cable system without dialing into the cable system. Thus, the initial connection to the Internet is much faster compared to using plain old telephone service.
In addition, cable modems allow for much faster information exchange than is available over plain old telephone service. An individual cable modem end user may experience information exchange speeds of from 0.5 Mbps to 1.0 Mbps or more depending on the cable network architecture and traffic load. This represents a speed that is at least an order of magnitude faster than is currently available over plain old telephone service. Furthermore, cable information exchange speeds may be further increased due to future improvements in cable technology. Thus, cable modems provide a low cost, high-speed alternative for Internet access.
Typically, the cable networks are considered “open,” meaning that any particular cable modem is likely to encounter some incoming data packets that are addressed to the computer system associated therewith and other data packets addressed to unrelated computer systems. The cable modem uses address filter information to filter the incoming data packets to allow passage for only those data packets that are addressed to the computer system associated with the cable modem.
This filtering avoids unnecessary processing of packets that are not addressed to the computer system associated with the cable modem. However, this filtering assumes that the cable modem is aware of the address of all of its associated computer systems. However, on occasion, the cable modem may not be aware of the correct address of an associated computer system. In this case, the packet addressed to that computer system would be filtered out by the cable modem, leaving the incoming message undelivered. Although the cable modem may possibly be manually reconfigured to accept packets addressed to the computer system, the user associated with the computer system may not ever know that a message was undelivered and so might remain unaware of the problem for quite some time.
In light of this difficulty with the prior art, there is a need for systems and methods for automatically correcting or updating address filter information. It would be advantageous if such systems and methods could be used to maintain current address filter information as a new computer is added to a group of locally networked computers that receive network services from a cable modem.